Landscaping with Native Kansas Oaks

Filtered light coming through a stately open-grown burr oak.

There are many appealing reasons to consider landscaping with native Kansas oaks. Oaks are

  • long-lived with strong branches,
  • can grow to be large and stately,
  • provide welcome shade from the hot Kansas summer sun,
  • allow some filtered light to pass through to allow growth of understory vegetation, and
  • enhance the wildlife diversity in any landscape by attracting insects.

Native Kansas Oaks

Kansas is predominately a prairie state. Fire and grazing have helped keep grasses and wildflowers as the dominant form of vegetation for thousands of years. Kansas does, however, get enough precipitation to support trees, especially many drought-tolerant species of oaks. And when they are not being burned or grazed down to the ground on a regular basis, they can thrive here.

With the Rocky Mountain rain shadow influencing the precipitation map for Kansas, we have increasing bands of precipitation moving from west to east across the state.

Trees generally need more water than prairie grasses and wildflowers. Therefore, it is understandable that eastern Kansas climate is most hospitable for growing trees. The following Küchler Vegetation Map of Kansas confirms the association between greater precipitation and the historical presence of trees by the location of oak-hickory forests, oak savannas, and other timbered regions in the eastern part of the state.

The trees that thrive throughout eastern Kansas may also be able to grow further west into Kansas, but will be limited to locations near streams or urban landscapes where they can receive supplemental irrigation.

Using the fantastic recently published book, Trees, Shrubs, and Woody Vines in Kansas by Michael Haddock and Craig Freeman, I compiled the following table of the oaks native to Kansas. I have listed the 12 native oak species in order from most to least common in Kansas. I did this to serve as a guide to the species that generally have the greatest tolerance to drought conditions and that are therefore more likely to succeed even in the drier parts of the state.

Attracting Wildlife

Regarding the benefits of oaks I provided in the introduction, I want to expand a bit on the benefits of attracting wildlife.

Filtered light sustains understory vegetation

Oaks in general and especially more drought-tolerant oaks like burr oak allow more light to filter through its leaf canopy to the understory than other tree species such as elms and maples. As I describe briefly in a post about a local, large burr oak tree, burr oak savanna plant communities of Eastern Kansas were historically able to support diverse arrays of grasses and wildflowers under their canopy that promote a healthy ecosystem of biological diversity. Urban folks can follow this model and grow prairie-like native plant gardens under the canopy of oaks. This also helps explain why it is easier to grow turf grass in the filtered light conditions under an oak than it is under the shadier understory of an elm or maple.

Oaks – the best trees for supporting wildlife

Professor Doug Tallamy in the Department of Entomology and Wildlife Ecology at the University of Delaware is a big proponent of using native oaks to attract wildlife. His book Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens makes a strong case for using oaks to attract caterpillars, and subsequently birds that feed caterpillars to their young, to enhance the biological diversity of a landscape. His research shows that the oak genus (Quercus) attracts more caterpillars to its leaves, flowers, bark, acorns, and roots than any other genus of trees. In fact, this genus is so important to Tallamy that his most recent book The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees focuses entirely on the subject.

Five Favorite Oaks

While I think there are appealing components to all 12 of the native Kansas oaks, I have narrowed my focus for the purposes of this post to promoting five favorite oak species.

USDA maps denote the natural range of each species. A given tree may still thrive in say an urban area outside of this range when offered wind and drought protection from structures, other trees, and/or supplemental irrigation.
This 55′ wide by 45′ tall burr oak outside my office window is great example of how this species takes a wide-open stance when grown in full sun. The root structure cross-section drawing pasted proportionately below this tree was found in the Nebraska Conservation Bulletin Number 37.

Burr oak savannas were part of the focus of my graduate research and I simply love the majestic, strong-branched open-grown shape of this species. The shape and distinct look of a mature Q. macrocarpa specimen in winter is as interesting to me as its leafy green look during the growing season. It is bimodal in its moisture distribution, meaning it can survive in both dry upland conditions as well as low floodplain conditions. Thick, gnarly bark makes this tree more fire tolerant than most, and when top-killed, its taproot allows it to immediately re-sprout. The large acorn fruits (hence the Latin name “macrocarpa“) are food for many insects, mammals, and birds (e.g., turkeys and wood ducks). To appreciate the value of a burr oak to wildlife, click on this Illinois wildflowers link and scroll down to the impressive list of “faunal associations.” Burr oak leaves turn yellowish-brown before dropping in the fall.

The attractive ashy gray bark, toothy margined leaves and stately round shape of the drought-tolerant chinquapin oak make it an appealing landscaping tree. One-inch sweet acorns are a favorite food for many birds and mammals and the leaves turn yellow-orange to orangish-brown before dropping in fall. This species prefers well-drained soils but tolerates a variety of soil textures and moisture regimes.

Dwarf chinquapin oak only reaches a mature height of approximately 20 feet and certainly can be used in different landscaping scenarios than any of the four other medium to large landscaping trees recommended here. You may use it as a featured shrub or planted with many to form a screen. This species prefers sandy or clayey soils whereas the larger Q. muehlenbergii does best in calcareous soils. In spite of its small size, dwarf chinquapin oak can produce large quantities of acorns which along with the leaves and bark provide food for numerous species of insects, birds and mammals. This oak is known to produce underground runners to spread clonally.

Black oak is named for its dark bark color at maturity. It has a deep taproot with widespread laterals which make it a very drought-tolerant tree that is adaptable to a variety of soil types. It does especially well in sandy soils. As described for other oak species, black oak provides food for numerous insects, birds and mammals.

Shumard oak is a popular landscaping tree because of its strong branches, long life and red fall color. It is adaptable to a variety of soils and its acorns provide food for various types of wildlife including insects, birds, and mammals. Although its natural environment is along streams in Eastern Kansas, it is tolerant of drier areas further west in protected urban areas. A shumard oak I planted in my yard loses its leaves late fall, by around Thanksgiving.

Things to Think About

Tree size/location

When locating a tree, leaving room for the eventual size of the mature tree will save you or future caretakers time and money. Conflicts between growing tree branches and buildings, utility wires, city code street clearances, and branches of other trees can lead to tree trimming headaches, so consideration given to a tree’s height and spread is important. Also, the closer a tree is to a sidewalk or driveway, the more likely its roots are to alter the grade of and contribute to the cracking of that concrete.

How long will it hold its leaves?

Some oaks lose their leaves in fall, but others hold onto them until spring. I can think of a couple of reasons this may be important to you. If you like to do your leaf raking in fall, don’t choose an oak that holds leaves till spring. If you want your oak to cast shade in summer but not winter, be sure to choose an oak that drops its leaves in fall. For example, this may be an important consideration for a tree that shades a house in summer, but allows solar panels to work in the winter.

Oak leaves are slower to decompose

Know that oak leaves have higher tannin content than many other tree species, and therefore, take longer to decompose. I like to use all my tree leaves for garden mulch and since the oaks I’ve planted in my landscape are all pretty small still, this has not been a big concern. However, if you compost your leaves or have heard the myth that tannin-rich oak leaves will make your soil more acidic, read this article.

Slower growing trees still provide rewards

A common complaint I hear about oaks is that they grow too slow. Therefore, folks may opt for the short-term gain of quick shade provided by a poplar or silver maple instead of a longer lived oak. A poplar lifespan may be 30-50 years, a silver maple 50-100 years, and an oak 150-250 years. But what you gain in quicker shade with the poplar and silver maple, you give up in durability, attraction to wildlife, and passing along quality trees to future property owners. The above recommended oaks all would be considered slow to moderate rate growing trees. Do know that you can increase the growth rate of an oak with mulching, supplemental water, and fertilizer. Maybe it is the skewed perspective of an oak lover, but I would think that oaks even improve property value. And remember, a tree is planted for the next generation as much as it is for you.

Landowner Prairie Restoration Spotlight – Carolyn and Terry Schwab

Terry and Carolyn Schwab live on 109 acres in Eastern Harvey County affectionately known by a former neighbor as the “Foothills to the Flint Hills.” While much of the county land has been converted to cropland over the last century, the Schwab property has remained in remnant prairie.

We received a grant in 2004 to identify and study more than 100 prairie remnants in South Central Kansas and to collect seed for our 18-acre Prairie Window Project prairie reconstruction project on-site at Dyck Arboretum. Until 2010, this work helped us develop a prairie landowner network through which we consulted with landowners and assisted them with their prairie management needs. It was during these years that I had the pleasure of first meeting the Schwabs. Ever since I have enjoyed observing the dedication they bring to being prairie restorationists and natural area enthusiasts.

Terry and Carolyn Schwab and the property they manage (2007)

Increasing Wildlife Diversity

The property was a moderately overgrazed cattle pasture when they acquired it in 1993. The Schwabs’ main goal as land stewards was to increase wildlife diversity through improved habitat and enhance their avid hobbies of bird-watching and fishing.

The remnant prairie and emergent wetland above and around the ponds on their land can consist of hundreds of species of grasses, wildflowers, sedges, and shrubs. High plant diversity translates to high wildlife diversity. Maintaining diverse herbaceous vegetation also serves as a good surface water filter that improves pond health. Terry and Carolyn knew that without grazing or other forms of grassland management, invasion of a handful of tree species (including nonnative species) would create a dense, and comparatively lifeless, forest canopy within decades. Plant species diversity would decrease and wildlife habitat would suffer. They needed to become prairie restoration land stewards.

Dotted gayfeather (Liatris punctata) (Photo by Carolyn Schwab)

Vegetation Management

Controlling woody species and removing nonnative wildflowers became top priorities for the Schwabs in their quest to improve wildlife habitat on their property. Their initial efforts were extensive and laborious. They cut Osage orange and eastern red cedar trees and manually dug out musk thistle. To maintain water levels in the ponds, they repaired holes in the dams and removed trees whose roots can compromise dam life.

Numerous small trees invading in prescribed burning units A and B (2002 aerial photography)
Comparison with the previous photo shows that mechanical removal and prescribed burning have reduced tree cover over a six-year period, especially in units A and B (2008 aerial photography)

They were able to open up the upland areas where they had successfully removed mature trees and restore contiguous areas of grass and wildflower-dominated prairie. In these areas, the Schwabs implemented a regular rotation of mowing and prescribed burning to control any further invasion of woody plants. They networked with a local fire department to help them do this. They found mowing and burning to be much less labor-intensive than manual tree removal and effective tools for long term tree management.

Management Unit B, post-burn in 2009 (Photo by Carolyn Schwab)

Carolyn and Terry have made great improvements in restoring the prairie and emergent wetlands with tree management, but they know that they cannot rest on their laurels. Mature, seed-producing trees on their land and neighboring properties make keeping up with tree invasion a continual challenge. In addition to maintaining a routine of mowing and burning, they continue to cut and treat a number of invading tree species including honey locust, Bradford pear, Osage orange, Siberian elm, eastern red cedar, and the shrub Japanese honeysuckle. They are also on the lookout for the highly invasive, noxious weed sericea lespedeza which is becoming increasingly present in the area.

Conducting a prescribed burn on Unit C in 2010

Wildlife Monitoring

Carolyn invests a great deal of time monitoring and reporting on the biodiversity observed on their property. Daily walks to document bird populations, track phenology of flowering plants, and photograph butterflies are all part of what she sees as being an informed land steward.

Regal fritillary butterflies are dependent on habitat including diverse, large tracts of prairie. Even though the Schwabs have been improving the habitat of their prairie, regal fritillary numbers seem to be declining in recent years on a landscape scale. Carolyn has been planting nectar plants like butterfly milkweed and regal fritillary host plants (prairie violets) in the landscaping around her house to try and further support regal fritillary numbers.

This 2013 regal fritillary on butterfly milkweed (a yellow native landscaping variety near house) was the last one that Carolyn has seen on her property (Photo by Carolyn Schwab)

Carolyn is a top-notch birder. According to the Kansas Bird Listserv Database, a total of 329 species of birds have ever been documented as observed in Harvey County. Carolyn has seen more of these species (270) than anybody. And with easy access to 109 acres of prairie, wetland, woodland, and open water habitat, Carolyn has seen a whopping 232 of these species on her property!

A favorite experience of hers was witnessing a rare event on October 27, 2010. Eastern Harvey County is well east of the main sandhill crane migration flyway and seeing cranes there is not common. That night, however, the Schwabs observed 200+ sandhill cranes settle in for the night at their pond and enjoyed hearing their calls through the night. The cranes took off the next morning, but left behind a lasting memory for Carolyn.

Return of Butterfly Milkweed

The Schwab prairie restoration efforts are not only increasing the presence of grassland bird populations, but plant diversity as well. For years, they have not seen any butterfly milkweed on their property. But during the growing season of 2020, Carolyn reports that she has seen 20 plants.

Butterfly milkweed (Photo by Carolyn Schwab)

Protection for the Future

The Schwabs are considering registering their property with the Kansas Land Trust to protect this native prairie in perpetuity. By establishing a conservation easement on the property, Terry and Carolyn would be establishing guidelines for future landowners to follow that would help protect the prairie, watershed, and the diversity of species therein.

Thank you, Carolyn and Terry for your important prairie restoration land stewardship and for being willing to share your story.

A white-tailed deer doe and two fawns sheltering on one of the Schwab pond islands (Photo by Carolyn Schwab)

Winter Prairie

Temperatures are cold, hours of darkness are long, and January is a nice time to observe the following beneficial features of a winter prairie garden.

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  • Habitat for micro-wildlife – Insect eggs persist and survive on residual vegetation – a good reason for leaving thatch on site when cutting it in the spring. For animals that don’t hibernate or achieve some form of dormancy, extant biomass provides insulation for body heat, protection from wind, and visual cover from predators; seeds provide an important source of food for small birds and mammals, and these animals will eventually feed others in the food chain.

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  • Vegetation buffer – Dormant plant matter provides an above-ground blanket or biomass buffer that reduces soil moisture loss, and slows changes in temperature. This effect improves chances of winter survival for wildlife, and the roots of living, dormant perennial plants.

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  • Developing seed bank – Allowing seed heads to persist on site, relax, and drop their seeds builds an inventory of propagules in the soil that can produce new seedlings in the future.

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  • Aesthetic beauty – Unique textures, variations of drab colors, organic ways of holding ice and snow, and even some landscape “disorder” provide interesting features for traditional yards that generally lack winter interest.

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Winter Prairie Hoarfrost

Be sure to enjoy the subtle nuances of the dormant prairie in winter over the next couple of months.

Happy new year,

Brad